Due to disease, insult or other causes, a person's renal system can fail. Renal failure causes several physiological complications. The balance of water and minerals, and the excretion of daily metabolic load are no longer possible in renal failure. During renal failure, toxic end products of nitrogen metabolism (e.g., urea, creatinine, uric acid, and others) can accumulate in blood and tissues.
Kidney failure and reduced kidney function have been treated with dialysis. Dialysis removes waste, toxins and excess water from the body that would otherwise have been removed by normal functioning kidneys. Dialysis treatment for replacement of kidney functions is critical to many people because the treatment is necessary to sustain the person's life. A person with failed kidneys cannot continue to live without replacing at least the filtration functions of the kidneys.
Two general types of dialysis therapy for treating patients with kidney failure are now in widespread use. One type, hemodialysis, provides for removing waste products by passing the blood of a patient through an appropriately constructed dialyzer unit located in an extracorporeal circuit. A second type of dialysis therapy, peritoneal dialysis, utilizes the membrane in a patient's peritoneal cavity for the purpose of separating waste products from the patient's fluid systems.
Hemodialysis treatment removes waste, toxins and excess water directly from the patient's blood. During the hemodialysis procedure, a trained health care professional will monitor the arterial and venous pressure of the patient in the extracorporeal circuit. Pressure is monitored in the extracorporeal circuit using a pressure transducer. Often, the transducer is placed at the end of a tube connected to a respective arterial or venous drip chamber. The pressure transducer measures air pressure, which is indicative of blood pressure. It is important that the blood not contact the air pressure transducer. One reason for this is to prevent cross-contamination between patients and provide a sterile barrier to reduce the risk of contamination by virus-infected blood in a liquid and/or aerosolized state. The barrier also filters particles, which might be entrained in an air stream and which could possibly be fed back to equipment within the dialysis machine.
Transducer protectors are made by assembling their constitutive parts, which may include a separation membrane and a housing for containing the membrane. One way of making transducer protectors is disclosed in U.S. Pat. No. 6,536,278. This patent discloses a transducer protector made from a membrane that is assembled to two housing halves. It is very important that there are no leaks of blood between the membrane and the housing in order to prevent transmission of the blood to the far side of the membrane and contamination of the pressure transducer. Assembling the transducer protector in this way does not allow for inspection of the seal between the membrane and the housing.
What is needed is a transducer protector to prevent contact between the blood and the transducer, thus preventing contamination of the transducer, and a better way to make the transducer protector. The transducer protector should be an in-line sterile barrier that can be placed between the transducer and the blood of the drip chamber to prevent blood or other liquid within the extracorporeal circuit from contaminating the pressure transducer.